You're setting up a High Availability (HA) VPN between your Google Cloud environment and your on-premises network. Despite having full administrative access to both the GCP networking components and your on-prem firewall devices, the VPN tunnel is failing to establish. In the Google Cloud Console, the tunnel status shows “Negotiation failure” and “BGP is down.” To investigate, you query Cloud Logging using: resource . type = "vpn_gateway" resource . labels . gateway_id = "TUNNEL_ID_NUMBER" In the logs, you frequently see entries like: log name : …/ logs / cloud . googleapis . com % 2Fipsec _events type : "vpn_gateway" textPayload : "received NO_PROPOSAL_CHOSEN notify, no CHILD_SA built" Based on these log messages, what action should you take to resolve the VPN connection issue?